Abstract : A search of MH-53E and CH-53E roll angle, ball width, and sideslip data was conducted in order to establish Fleet steady heading sideslip (SHSS) NATOPS limits for aircraft lacking nose booms. No ball width data were found for the CH-53H. Plots of the available information were sent to NAVTESTPILOTSCH (Bob Miller). He suggested that the data (three different slopes) might be normalized to one slope, using a velocity squared ratio as is done for fixed-wing aircraft. Doing this collapsed the data to a single line. An NH data plot was made (roll angle versus ball width - believed to be linear for SHSS conditions) and used to calculate CH ball width from roll angle data. AH-lW data to 125 KIAS containing ball 'pegged' (against the limit of travel) points were handled similarly, allowing extrapolation to 170 KIAS. A family of curves was then generated (both course and fine) for the Cobra as a function of airspeed. Finally, lateral g sensitivity was derived from a plot of ball width versus roll angle, allowing correction of a lateral g-driven (accelerometer) ball indication in a helmet mounted display. This process is recommended for use in handling roll angle and ball width information in flight simulations. Consideration should be given to incorporating this method into the NAVTESTPILOTSCH curriculum.